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Journal of Vertebrate Paleontology 21(4):730–739, December 2001
q 2001 by the Society of Vertebrate Paleontology

AN ASSOCIATED SPECIMEN OF CARCHARODON ANGUSTIDENS (CHONDRICHTHYES,
LAMNIDAE) FROM THE LATE OLIGOCENE OF NEW ZEALAND, WITH COMMENTS ON
CARCHARODON INTERRELATIONSHIPS
MICHAEL D. GOTTFRIED1 and R. EWAN FORDYCE2
Michigan State University Museum, East Lansing, Michigan 48824-1045, USA;
2
Department of Geology, University of Otago, P.O. Box 56, Dunedin, New Zealand
1

ABSTRACT—An associated specimen of the large fossil lamnid shark Carcharodon angustidens from the Late Oligocene of New Zealand’s South Island preserves approximately 165 teeth, and 32 vertebral centra, making it one of
the most complete Tertiary lamnids recovered to date, and the most complete fossil shark known from New Zealand.
The well-preserved dentition allows for a more thorough description and revised interpretation of the dental morphology
of this relatively poorly known species, and the partial vertebral column permits the unequivocal relating of teeth and
centra for this taxon. Based on dental and vertebral morphology, C. angustidens is here considered to be properly
assigned to the genus Carcharodon, which also includes several other ‘‘great-toothed’’ Tertiary shark species and C.
carcharias, the extant Great White Shark. According to this interpretation, Carcharodon has a record extending back
to the early Tertiary; this is in sharp contrast to an opposing view, which holds that the genus evolved much more
recently, at the Miocene–Pliocene boundary, and that C. angustidens and the other great-toothed forms should be placed
in a separate genus (‘‘Carcharocles’’).

INTRODUCTION
The genus Carcharodon Smith in Mu¨ller and Henle, 1838
(Family Lamnidae) includes the extant Great White Shark Carcharodon carcharias (Linnaeus, 1758) and, according to several
authors (see below), a number of Tertiary species—often referred to collectively as the ‘‘great-toothed’’ sharks—that are
assigned to the genus primarily on the basis of possessing large,
triangular, evenly serrated teeth similar to those of living white
sharks. An alternative view, expressed by (among others) Muizon and DeVries (1985), Cappetta (1987), and Stewart and Raschke (1999), holds that the genus Carcharodon originated relatively recently, in the late Miocene–early Pliocene, as a direct
descendant of another lamnid, the fossil Mako Isurus hastalis.
Adherents of this view usually place the great-toothed fossil
species in the genus Carcharocles Jordan and Hannibal, 1923.
For reasons discussed further below, we follow Keyes (1972),
Applegate and Espinosa-Arrubarrena (1996), Gottfried et al.
(1996), Gottfried (1998), and Purdy et al. (2001), as well as
many earlier workers (e.g., Leriche, 1910), and place the fossil
great-toothed sharks, including the material detailed here, in
Carcharodon.
Some 96 nominal species of living and fossil sharks have
been assigned to Carcharodon, although at present only eight
or nine of these are generally considered to be distinct (Applegate and Espinosa-Arrubarrena, 1996; Purdy et al., 2001). The
best-documented of the fossil species are C. auriculatus (Eocene), C. angustidens (Oligocene), C. subauriculatus (early
Miocene), and C. megalodon (late Oligocene–Pliocene). Fossil
Carcharodon teeth have been reported in Tertiary marine deposits from North and South America, Europe, Africa, Japan,
Australia, and New Zealand, suggesting that the genus has a
long history of amphitemperate circumglobal distribution in
coastal marine environments, similar to that of extant C. carcharias (Compagno, 1984).
Despite their broad temporal and geographic distribution, our
knowledge of fossil Carcharodon, and of Tertiary sharks in
general, is largely limited to isolated teeth due to the low preservation potential of their cartilaginous skeletons. Reliance on
isolated teeth has led to the erection of many dubious taxa,

which cloud our understanding of fossil shark diversity and
hamper systematic studies. Additionally, it is often impossible
to unequivocally assign isolated vertebral centra, which are
well-calcified and often fossilize (Gottfried, 1999), to taxa
erected on the basis of isolated teeth. For these reasons, associated fossil shark specimens are noteworthy and should be described. This report documents such an association, comprising
both much of the dentitition and a partial vertebral column, of
the large Oligocene lamnid Carcharodon angustidens.
The material described here was found in the Late Oligocene
of New Zealand’s South Island and is one of only a small number of associated fossil Carcharodon specimens, and the most
complete fossil shark that has been recovered from New Zealand (see Keyes, 1972, for an historical review of New Zealand
fossil Carcharodon records). Since the mid-1980s, Fordyce and
associates have systematically prospected South Island Late Oligocene sites, and, among the hundreds of fossil vertebrates
identified, only a few isolated Carcharodon teeth had been recovered prior to the associated individual described below.
MATERIALS AND METHODS
The Carcharodon angustidens specimen described here is
housed in the University of Otago Department of Geology paleontology collections (catalogued as OU 22261). The ten adjoining blocks containing teeth and vertebrae, plus associated
teeth found loose in immediately surrounding matrix, were collected by R. E. Fordyce, A. Grebneff, B. V. N. Black, H. Ichishima, J. Daniels, C. M. Jenkins, G. B. McMurtrie, G. Curline,
and S. Rust, on 9 February 1994, and 4–6 and 9 January 1995.
Blocks were removed using pneumatic chisels, a masonry saw,
and rock drill with plug-and-feather wedges, transported in
plaster jackets, and mechanically prepared, mainly by A. Grebneff, at the Department of Geology, University of Otago. Photographs were taken with a Pentax SPII camera using a 50 mm
macro lens; line art is not corrected for possible parallax. Drawings of the teeth and centra on the blocks were made by tracing
onto clear plastic film set on a glass plate immediately above
the specimen.

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GOTTFRIED AND FORDYCE—LATE OLIGOCENE CARCHARODON FROM NEW ZEALAND

731

FIGURE 1. Map diagram of associated Carcharodon angustidens specimen (OU 22261) as found in the field, showing association of teeth and
vertebral centra.

SYSTEMATIC PALEONTOLOGY
Class CHONDRICHTHYES
Subclass NEOSELACHII
Order LAMNIFORMES
Family LAMNIDAE
Genus CARCHARODON
CARCHARODON ANGUSTIDENS (Agassiz, 1843)
Referred Material OU 22261 (Figs. 1, 3), an associated
specimen consisting of approximately 165 teeth (including
some fragmentary remains) and 32 vertebral centra (some incomplete), along with several indeterminate pieces of what appear to be poorly preserved cartilage. The specimen is mainly
distributed over the surface of ten adjoining blocks of matrix
(Fig. 1), with the exception of approximately 40 of the teeth
(some fragmentary) that were recovered from loose sediment
around the blocks. The physical proximity, identical color and
preservation, and size relationships all indicate that the teeth
and centra of OU 22261 represent the associated remains of a
single individual.
Revised Diagnosis A lamnid shark differing from others in
the group by the following combination of characters: teeth
slender, upper anterior teeth largest and lower anterior teeth
approximately twice as high as their width at the base of the
crown; lower anteriors more symmetrical and narrower in proportion than upper anteriors; apices of lateral and posterior teeth
posteriorly recurved, with recurvature strongest in posterior lateral teeth; lateral denticles well-developed as sharp triangular
peaks but may also form low, rounded ridges on some teeth;
lateral denticles project at acute angles relative to the crowns;

distinct notch, which may be subdivided into secondary notches
on some teeth, separating lateral denticles from crowns; crowns
evenly and finely serrated, except for small posterior teeth
which may be coarsely serrated or lack serrations; lateral denticle serrations coarse to fine, to absent on small posterior teeth;
vertebral centra with thick-walled articular cones connected by
eight to twelve radiating lamellae; middle of each centrum with
distinct sunken circular depression, marking the notochordal
constriction.
Comment on Agassiz’ Original Description of Carcharodon angustidens Agassiz’ (1843) characterization of this species focused on the slender proportions of the teeth relative to
other species of Carcharodon; he noted that the height of some
of the teeth measured approximately twice their width, a feature
included in the revised diagnosis above, and that the width of
the enamel never exceeded the height of the tooth above the
root. He also emphasized the well-developed lateral denticles
on this species. OU 22261 conforms to Agassiz’ original description of C. angustidens, and the anterior teeth of OU 22261
closely resemble his figured type series (compare Agassiz,
1843:figs. 20–25, with Fig. 3J herein). Agassiz did not, however, have an associated dentition to work from (the origin and
present whereabouts of the three lower? anterior teeth that
formed his type series are unknown), or vertebral centra; information from the associated specimen described here is reflected in the above revised diagnosis. Leriche (1910) commented on Agassiz’ original description, in essence agreeing
that the slender proportions combined with lateral denticles of
the teeth were sufficient to distinguish C. angustidens from other similar species.

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Comparison with Other Carcharodon Species Carcharodon angustidens, as represented by the specimen described
here, is readily distinguished from other large lamnoid species,
which are the only taxa with which it could plausibly be confused. It is significantly larger and geologically younger than
C. orientalis (a Paleocene–?Eocene form) or C. auriculatus
(Eocene), and its teeth are proportionately much narrower, and
have much finer serrations, than teeth of either of those two
species. Carcharodon angustidens lacks the unusually expanded, bulbous, highly asymmetrical root identified by Applegate
and Espinosa-Arrubarrena (1996) as characteristic of upper anterior teeth of the early Oligocene species C. sokolowi (assuming C. sokolowi is a distinct species). Carcharodon angustidens
is smaller than C. subauriculatus (Early Miocene) and C. megalodon (Late Oligocene–Pliocene), and also has proportionately narrower teeth than those two species. In addition, those
two species do not show as consistently strong development of
lateral denticles (although lateral denticles may be present in
either). Finally, C. carcharias (Miocene–Recent) is a geologically younger and smaller species, which has more coarsely
serrated teeth that typically lack lateral denticles as adults, and
less strongly developed root lobes.
Assignment of Carcharodon angustidens to Lamnidae
Glikman (1964) assigned ‘‘Carcharodon’’ angustidens (and
‘‘Carcharodon’’ auriculatus) to the genus Otodus, which, along
with the ‘‘false Mako’’ Parotodus benedini (see Kent and Powell, 1999, who describe an associated dentition of P. benedini)
constitutes the Family Otodontidae. Purdy et al. (2001) summarized the case against this assignment, and we agree with
their position on this issue. We also note that OU 22261 appears
to have two upper anterior teeth, separated from the lateral series by a smaller intermediate tooth; this configuration has been
identified by Compagno (1984:237) as a diagnostic feature of
the Family Lamnidae.
Locality, Geologic Setting, and Age OU 22261 was collected from the top of a small mesa, at Island Cliff Farm near
Tokarahi, North Otago, South Island, New Zealand (Fig. 2).
New Zealand Map Series NZMS 260 grid reference 141 (1984)
255811; near latitude 448 589 S, longitude 1708 599 E.
The specimen was recovered from a thin shell bed (dominated by the smooth-shelled pectinid Lentipecten hochstetteri)
in the otherwise sparsely macrofossiliferous glauconitic lower
part of the Upper Oligocene (New Zealand Stage Duntroonian)
Otekaike Limestone Formation (of Gage, 1957) (Fig. 2). Age
is approximately middle Chattian, middle Late Oligocene. The
shark-bearing horizon is 9.9 m above the locally-exposed base
of the Kokoamu Greensand; the total sequence at the site is
approximately 25 m thick (Fig. 2). The unique fossil record
number for this horizon and locality is I41/f161 (New Zealand
fossil record file, Geological Society of New Zealand). The site
has produced a diverse marine vertebrate fauna, including other
neoselachian sharks, teleost fishes, penguins, and cetaceans.
The matrix in which OU 22261 is preserved is a light green,
moderately cemented, massive, well-sorted very fine sandstone
(carbonate-cemented glauconitic calcarenite), which yields rare
Globoquadrina cf. G. dehiscens, a planktic foraminiferan
whose first appearance datum marks the base of the local Waitakian Stage (Hornibrook et al., 1989), and which is known to
appear in the middle Otekaike Limestone elsewhere in North
Otago (Graham et al., 2000). Rare Globigerina euapertura indicate an age no younger than basal Waitakian. The presence
of rare Globoquadrina cf. dehiscens is not given much stratigraphic weight, for the sample also contains an ostracod close
to or conspecific with Cytheralison amiesi which characterises
the immediately older Duntroonian Stage (Ayress, 1993). The
presence of C. amiesi is unsurprising in transitional Kokoamu
Greensand/Otekaike Limestone. Further, the 87Sr/86Sr ratio for
a well-preserved Lentipecten shell associated with the shark is

0.708138 6 12, which indicates an age of approximately 26.0
Ma. We conclude that the shark horizon represents the upper
part of the local Duntroonian Stage (5middle Chattian).
Description
Dentition OU 22261 preserves approximately 165 teeth
(including some that are fragmentary), which range in size from
large upper anteriors nearly 100 mm in height, to a very small
posterior tooth 7.3 mm high. A representative sampling of upper and lower teeth from different positions is shown on Figure
3; measurements for these teeth are given in Table 1 (complete
measurements of all teeth are available from the senior author
on request). Some teeth are preserved only as thin enamel
shells, which are splintery in appearance, often somewhat
crushed, and lack roots—these represent replacement teeth that
likely had formed just prior to the death of the shark, and were
probably separated by two or more intervening teeth from the
functional tooth position for their file. The serrated edges of
these new replacement teeth are well-formed, and often separated from the rest of the crown by a regular crack that runs
the length of the crown edge, which suggests that, as the replacement teeth form, the enamel along the serrated edges becomes strongly developed before that of the lingual and labial
surfaces.
The teeth of OU 22261 have well-developed lateral denticles,
in many cases with the lateral denticle set off from the crown
by a sharp notch, and with the denticle oriented at an acute
angle relative to the crown (features of C. angustidens mentioned by Agassiz, 1843, in his original description of the species). However, there is considerable variation in the nature of
this specimen’s lateral denticles (not recognized by Agassiz because he had only a few teeth rather than an associated dentition, and not indicated on Applegate and Espinosa-Arrubarrena’s [1996:fig. 10] artificial tooth set for the species): on some
teeth, the lateral denticles are relatively low, rounded ridges, set
off from the crown by a shallow depression rather than a sharp
notch, on some the denticle is more sharply peaked, and on
some the lateral denticles are subdivided by secondary notches
(Fig. 4). Generally, the serrations on the lateral denticles are
coarser than those running along the edges of the crowns. The
number of serrations ranges from approximately 100/side on
larger anterior teeth, to no serrations at all on the smallest posterior tooth preserved (which has a height of 7.3 mm).
Based in part on comparison with the dental morphology of
the extant species Carcharodon carcharias (which we consider
a close relative of C. angustidens; see Discussion, below), and
the earlier work of Applegate and Espinosa-Arrubarrena (1996)
on C. angustidens, we interpret OU 22261 as having upper teeth
that are broader in proportion than the lowers; the two upper
anteriors are nearly symmetrical, the largest teeth in the jaws,
and are separated by a smaller reversed intermediate from the
lateral series. The upper laterals decrease regularly in size and
show increasingly strong posterior recurvature progressing from
the anterolaterals to the posterolaterals. The several posteriors
have very small crowns with relatively prominent, weakly serrated or unserrated lateral denticles, and, in the case of the
smallest posterior preserved, unserrated crowns as well. The
roots of the posterior teeth are thick and strongly developed,
and rather bulbous, for the size of the teeth. Based on size
differences and shape variation in the teeth that we interpret as
uppers, the tooth arrangement for the upper dentition in OU
22261 is hypothesized to be as follows: two anteriors, one intermediate, five laterals, and ?four posteriors.
The lower teeth are narrower in proportion than the uppers,
with a nearly upright, slender, very nearly symmetrical first
lower anterior, and second and third lower anteriors that are
slightly broader than the first and also show some posterior

GOTTFRIED AND FORDYCE—LATE OLIGOCENE CARCHARODON FROM NEW ZEALAND

733

FIGURE 2. Location of ‘‘Island Cliff’’ site (lower left), South Island of New Zealand, where the associated Carcharodon angustidens specimen
(OU 22261) was recovered, and biostratigraphic section (upper right) showing the position of the shark horizon relative to the Upper Oligocene
Otekaike Limestone and Kokoamu Greensand formations.

recurvature relative to the first lower anterior. The series of
progressively smaller and narrower laterals are not quite as
strongly posteriorly recurved as the upper lateral series, and are
markedly narrower, particularly the posterolaterals. The small
posterior teeth have strongly developed and rather bulbous

roots, small, coarsely serrated (or, in the case of the smallest
posteriors, unserrated) crowns, and prominent lateral denticles
(we recognize the difficulty in distinguishing upper vs. lower
posterior teeth, even in an associated specimen such as OU
22261). The tooth arrangement for the lower dentition in this

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 21, NO. 4, 2001

GOTTFRIED AND FORDYCE—LATE OLIGOCENE CARCHARODON FROM NEW ZEALAND
individual is interpreted as: three anteriors, six (or possibly seven) laterals, and three posteriors.
The relative completeness of the associated dentition from
OU 22261 leads to some comments on the artificial tooth set
for C. angustidens presented in Applegate and Espinosa-Arrubarrena (1996:fig. 10), which was based in part on Leriche’s
(1910) tooth series. Relative to Applegate and Espinosa-Arrubarrena’s figure, OU 22261 has slightly more robust upper anteriors, a somewhat larger intermediate tooth, slightly more posterior recurvature in the second and third lower anteriors, narrower lower laterals, and more variation in the shape and degree
of development of the lateral denticles. These differences are
reflected in the C. angustidens tooth set shown in Figure 5,
which is based on OU 22261. It is possible, even likely, that
other specimens may vary from OU 22261 in the exact arrangement of the teeth, particularly in the lateral and posterior positions, and in the shape of the teeth and the expression of the
lateral denticles. However, Figure 5 is based on an associated
individual, rather than an artificially assembled set, which
should help mitigate against the potential for errors that arise
from mixing teeth from individuals of different sizes, ages, and/
or genders.
Vertebral Centra Along with the dentition, OU 22261
also preserves a portion of the vertebral column, consisting of
32 complete to partial centra. These are mainly concentrated at
one end of the specimen (see Fig. 1). The centra (Fig. 6) are
of typical lamnid appearance, compressed in lateral view, and
with evenly concave articular faces that show well-developed
annuli. The centra are imperforate but bear very marked, distinctly sunken circular depressions running through their centers, indicating the position and extent of the notochordal constriction. The centra are not evenly circular, but somewhat oblong, with a slightly greater diameter dorsoventrally than laterally. Additionally, many of the centra are somewhat sheared
to one side, presumably from burial compaction. Prominent
paired foramina for the neural and haemal cartilages are situated
along the dorsal and ventral borders, respectively. The walls of
the articular cones are relatively robust, and are joined by radiating lamellae; the lamellae vary in thickness, but tend to be
thicker where they join the walls of the articular cones, and
thinnest in the middle. The number of lamellae situated between
adjacent neural and/or haemal foramina varies from eight to
twelve.
Two distinctly different size classes of centra are represented;
the majority of those preserved are relatively large (e.g., those
shown on Fig. 6), with maximum diameters ranging from 86 to
110 mm, and with lengths of 34 to 42 mm. Four of the centra
(two of which are too incomplete to accurately measure) are
much smaller and blockier in appearance, with diameters of 46
and 57 mm, and lengths of 32 and 34 mm, respectively. The
larger centra, based on their proportions, are likely from the
anterior region of the vertebral column, while the much smaller,
more blocky centra probably derive from the posterior trunk
and/or precaudal region and have been displaced anteriorly. The
large centra of OU 22261 have a greater diameter, and are
slightly longer than, an otherwise very similar-looking C. angustidens centrum from the Oligocene of Belgium, figured by
Leriche (1910), which measures about 80 mm in diameter. Liv-

735

TABLE 1. Measurements of selected Carcharodon angustidens (OU
22261) teeth; these are illustrated of Figure 3, and presented in the same
order (A–R) here. All measurements in mm. Abbrevations: r, right, l,
left; lab, labial; ling, lingual; in reference to side of tooth exposed.
Tooth height 5 perpendicular distance from the apex of the crown to a
straight line across the ventral-most extremity of the root lobes; width
5 greatest width across root. Measurements for all teeth are on file with
the senior author (MDG).
Height
lab

ing white sharks have 172 to 187 total centra, with the largest
in the midbody region (Gottfried et al., 1996), and very small
centra that extend out to the dorsoposterior tip of the heterocercal caudal fin, suggesting that the 32 centra preserved in OU
22261 likely represent approximately 15–20% of the total number that were present. As expanded on further below, the largest
centra in this individual may well have been far larger, up to
approximately 155–160 mm in maximum diameter.
DISCUSSION
Carcharodon in the New Zealand Fossil Record
Chondrichthyans are fairly well-represented in New Zealand
Tertiary marine strata (Davis, 1888; Chapman, 1918; Keyes,
1972, 1977, 1979, 1982, 1984; Pfeil, 1984; Fordyce, 1991).
Keyes (1972) reviewed occurrences of Carcharodon, which at
that time (and until this report) were based on isolated teeth.
He recognized two fossil Carcharodon species in New Zealand,
C. auriculatus from the Late Eocene, and C. megalodon from
the Oligocene–Pliocene, as well as C. carcharias which has a
Pliocene–Recent New Zealand record.
Several of the teeth that Keyes (1972) assigned to C. megalodon are dated as Oligocene (New Zealand stages Whaingaroan, Duntroonian, and/or Waitakian), which is significantly
older than the generally accepted Mio–Pliocene range for this
species (Applegate and Espinosa-Arrubarrena, 1996). In several
cases, the teeth in question are worn or incomplete, and lack
information on the development of lateral denticles and other
morphological details. We suggest that these incomplete Oligocene specimens should be assigned to C. sp. indeterminate.
However, Keyes (1972:fig. 10) includes a large upper anterior

←
FIGURE 3. Representative teeth of associated Carcharodon angustidens specimen OU 22261; note that some are shown in labial(lab) view, and
others in lingual(ling) view, depending on which surface of the tooth is exposed (the teeth are still in situ in the matrix, which is not shown here
for ease of viewing). See text for explanation of how tooth positions were inferred. Measurements for these teeth are given in Table 1. A, right
upper anterolaterallab; B, left upper anterolaterallab; C, left upper anterolaterallab; D, right intermediateling; E, left upper anterolaterallab; F, right upper
posterolaterallab; G, left upper posteriorlab; H, right upper posteriorling; I, left upper posteriorlab; J, right lower anteriorlab; K, left lower anteriorlab;
L, right lower anterolaterallab; M, left lower anterolateralling; N, right lower anterolaterallab; O, right lower anterolaterallab; P, left lower posterolateralling; Q; left lower posterolaterallab; R; right lower posteriorlab.

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 21, NO. 4, 2001
other material mentioned in Keyes (1972), several additional C.
angustidens and/or C. sp. teeth from South Island Oligocene
sites are present in the OU collections. Overall, these suggest
that C. angustidens was a regular component of the South Island’s Oligocene marine fauna, and that by the close of the
Oligocene it was joined and eventually supplanted by C. megalodon.
Length Estimates for Carcharodon angustidens
Gottfried et al. (1996) calculated a linear least-squares regression relating upper anterior (UA) tooth height: total length
(TL) for Carcharodon carcharias, as follows:
TL (m) 5 a 1 b[UA height (mm)],
where a and b, as calculated, are 20.22 and 0.096, respectively
(r2 5 0.96).
Assuming that C. angustidens had a UA height : TL relationship similar to that of extant white sharks, and given that
the largest upper anterior (UA) tooth in OU 22261 measures
98.7 mm in overall height, we estimate a TL for this shark as
follows:
20.22 1 0.096[98.7 mm] 5 9.3 m TL

FIGURE 4. Ventrolateral corner of three anterior teeth from OU
22261, to show a representative range of lateral denticle variation in
this specimen of Carcharodon angustidens. A, triangular lateral denticle
set off from main crown by distinct notch; B, more rounded, subdivided
lateral denticle with less distinct notch; C, low, undulating lateral denticle separated from main crown by a low ridge. All drawn from lingual
side.

The upper anterior teeth of C. angustidens are markedly larger than the largest C. carcharias tooth (62 mm height, from a
6.0 m TL shark) available in the sample (n 5 73) used to calculate the above formula. Gottfried et al. (1996) conservatively
estimated, in similar fashion, a TL of 15.9 m for large individuals of the giant Miocene species C. megalodon, which have
upper anterior teeth that reach a height of at least 168 mm.
Gottfried et al. (1996) also related vertebral centra dimensions to TL, as follows:
TL (m) 5 a 1 b[MVW (maximum vertebral width) mm],

tooth (OU 10768, 150 mm in height) from the Chatton Marine
Formation of Waimumu, Southland (South Island). OU 10768,
which we reexamined, appears to quite clearly be C. megalodon, and to be accurately dated as Late Oligocene (Duntroonian). This Waimumu tooth may well represent the oldest unambiguous record of C. megalodon. An additional C. megalodon tooth, OU 11833, from an unspecified but Late Oligocene
or older locality at ‘‘Maerewhenua’’ (probably the Maerewhenua River near Duntroon; see Fig. 2), further adds to the evidence presented by Keyes (1972) that this species has a preMiocene New Zealand record. Along with these teeth, and the

where a and b, as calculated, are 0.22 and 0.058, respectively
(r2 5 0.97) (based on a sample size of n 5 16; the relatively
small sample size is due to the scarcity of skeletonized white
shark specimens).
The largest of the 32 centra in OU 22261 measures ca. 110
mm in maximum width, giving the following result:
0.22 1 0.058[110 mm] 5 6.6 m TL
This much lower figure, 6.6 m vs. 9.3 m TL based on tooth
height, is likely the result of the largest centra not being preserved in OU 22261. Living white sharks have up to 187 total
vertebral centra, with the largest in the midbody region; the

Associated vertebral centra of Carcharodon angustidens, as preserved in situ on OU 22261.

largest centra in OU 22261 can be back-calculated (using the
above regression) and predicted to have a MVW of about 155–
160 mm, if the tooth-based TL estimate is reasonably accurate,
and again assuming that formulae derived from extant white
shark data can also be applied to the fossil species.

ceous genus Squalicorax [Family Anacoracidae]). This character distribution suggests that serrated teeth are a derived feature for the genus Carcharodon (including the fossil species).
Previously, in separate analyses that looked only at extant species, both Compagno (1990) and Long and Waggoner (1996)
interpreted serrations as autapomorphic for C. carcharias.

Lateral Denticles and Serrations
The presence or absence, and degree of development, of lateral denticles can be a useful feature for species-level diagnoses
and identifications within Carcharodon. Lateral denticles are
consistently well-developed in the geologically older species
(C. orientalis, C auriculatus, and C. angustidens). However,
lateral denticles also occur in early life stages of extant C. carcharias (Francis, 1996; Applegate and Espinosa-Arrubarrena,
1996; Uchida et al., 1996), which typically lack lateral denticles
when fully grown, and on some (primarily early to middle Miocene) teeth of C. megalodon (Purdy et al., 2001, and MDG,
pers. obs.). The pattern within Carcharodon is therefore towards reduction of lateral denticles, particularly in adults, but
they are found in at least some growth stages and/or on some
individual teeth in Carcharodon in general (in the sense that
the generic name is used in this paper, see below). Long and
Waggoner (1996) expressed a somewhat contrary view, interpreting the loss of lateral denticles in adults as a lamnid synapomorphy.
Within Lamnidae, fully and evenly serrated teeth are only
found in Carcharodon. In addition, none of the other sharks
within the Order Lamniformes (Cetorhinidae, Alopiidae, Megachasmidae, Odontaspididae, Pseusocarchariidae, Mitsukurinidae) possess serrated teeth (with the exception of the Creta-

The Fossil Great-Toothed Sharks: Carcharodon or
Carcharocles?
Considerable controversy has persisted in recent years regarding the correct generic assignment for the fossil greattoothed sharks. One school of thought, advocated some years
ago by Casier (1960), and adopted more recently by Muizon
and DeVries (1985) and Stewart and Raschke (1999), among
others, holds that the extant species Carcharodon carcharias
evolved directly from the fossil Mako Isurus hastalis (Isurus is
generally regarded as the sister-genus to Carcharodon within
lamnids [Compagno, 1990; Martin, 1996], and see Purdy et al.,
2001, for a review of fossil Isurus nomenclature). This view
has led to the idea that the fossil great-toothed sharks have an
evolutionary history somewhat separate from, and are not necessarily closely related to, the Great White Shark, C. carcharias. This then requires that the fossil species be placed in another genus, the usual choice being Carcharocles, erected by
Jordan and Hannibal (1923) to accommodate C. auriculatus
(see Purdy et al., 2001, for a detailed discussion of this nomenclatural history). Alternatively, the perspective reflected in
this paper is that the genus Carcharodon has a relatively long
evolutionary history, extending back to the Paleogene, and that
the several fossil great-toothed species, including C. angusti-

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JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 21, NO. 4, 2001
assigning the great-toothed species to Carcharodon, including
an ontogenetic gradation from coarser serrations (in juveniles)
to increasingly finer serrations (in adults), and the presence of
a chevron-shaped neck area on the lingual surface of upper
anterior teeth. In addition, vertebral centra of C. carcharias and
of fossil great-toothed lamnids, including C. angustidens and
C. megalodon, have a very similar internal calcification pattern
(Gottfried, 1999), although more comparative work is needed
on this feature. While the debate will no doubt continue, we
agree with Purdy et al. (2001) that the preponderance of morphological evidence supports the assignment of the fossil greattoothed species, including C. angustidens, to Carcharodon. A
final point in this regard relates to recent molecular data (Martin, 1996) which suggest that the genus Carcharodon diverged
from its common ancestor with Isurus at least 43 Ma, or about
40 million years earlier than the purported origin of C. carcharias from I. hastalis. While not directly testable with fossils,
these molecular data are congruent with the view advocated
here, that the fossil great-toothed species, including C. angustidens, are members of a monophyletic lineage that extends
back to the early Paleogene, and that includes C. carcharias,
the extant Great White Shark.
ACKNOWLEDGMENTS

FIGURE 7. Carcharodon carcharias, upper right anterolateral tooth
(National Museum of Natural History USNM 336204) in labial view
(also figured in Purdy, 1996:fig. 3D), from the middle Miocene Calvert
Formation, Kaufman Camp, Calvert County, Maryland. The tooth was
collected from bed 10 of the Calvert Formation; that horizon has been
dated at approximately 16 Ma (see Ward, 1992), meaning that this specimen predates the ‘transitional’ late Miocene/early Pliocene teeth from
Peru and California (see Discussion) by at least 10 million years.

dens, are members of this lineage and can be placed in Carcharodon.
A primary line of reasoning advanced in recent years to support the assignment of the great-toothed species to Carcharocles is the presence of partially serrated late Miocene teeth,
interpreted as transitional between unserrated Isurus hastalis
and fully serrated Caracharodon carcharias teeth. These have
been noted from the Pisco Formation of the Sacaco region of
Peru (Muizon and DeVries, 1985), and more recently from the
Capistrano Formation of southern California (Stewart and Raschke, 1999). According to Stewart and Raschke (1999), these
teeth show the direct anagenetic evolution of the genus Carcharodon from I. hastalis, at about the time of the Miocene–
Pliocene boundary. The implications of this are: (1) Carcharodon is monotypic, containing only C. carcharias, and (2) the
genus is no older than about 5 Ma.
We find this anagenetic evolution hypothesis problematic for
a number of reasons. The fossil record of teeth that can be
assigned to Carcharodon carcharias extends back into the middle Miocene (Fig. 7; also see Purdy et al., 2001; Purdy, 1996;
and Leriche, 1927), predating the supposed late Miocene–early
Pliocene origin of C. carcharias by about 10 million years.
Furthermore, the fossil great-toothed sharks share dental features (relative to Isurus, and Lamna, the other genus in Lamnidae) with C. carcharias, including nearly symmetrical upper
anterior teeth that are the largest in the jaws (larger than the
lower anteriors), and fully and evenly serrated teeth (as noted
above, the Cretaceous lamniform Squalicorax also has serrated
teeth, but this genus is not considered a lamnid). Purdy et al.
(2001) list a number of dental features shared between the fossil
great-toothed species and Carcharodon carcharias that support

We thank John and Dorothy Ottley of Takarahi for their generous assistance and for kindly permitting Fordyce and field
crews to collect at Island Cliff, and Bill and Judy Simpson for
accomodation. The sterling efforts of the field crews are greatly
appreciated. We thank Andrew Grebneff for his skillful preparation and enduring contributions to the project. Helpful comments and input were provided by Ian Keyes (Lower Hutt, New
Zealand), Robert Purdy (USNM, Washington, D.C.), Malcolm
Francis (NIWA, Wellington, New Zealand), and L. J. V. Compagno (South African Museum, Cape Town). We also greatly
appreciate the thoughtful critical comments provided by David
Ward (Orpington, England) and Kenshu Shimada (DePaul University, Chicago), whose views on fossil lamnid sharks differ
sharply from those expressed in this paper. Sunny Wang (Michigan State University) assisted with producing some of the figures.
Financial support to Fordyce for field work and preparation
was provided by the National Geographic Society Research
Fund (grant number 5381–94); preparation was also supported
by the Research Committee, University of Otago. Additional
support was provided (to Gottfried) by the Calvert Marine Museum (Solomons, Maryland) in the initial stages of this project,
and more recently by the Michigan State University Museum
and Department of Geological Sciences.
LITERATURE CITED
Agassiz, L. 1843. Recherches sur les poissons fossiles. Neuchaˆtel, 390
pp.
Applegate, S., and L. Espinosa-Arrubarrena. 1996. The fossil history of
Carcharodon and its possible ancestor, Cretolamna: a study in
tooth identification; pp. 19–36 in A. Klimley and D. Ainley (eds.),
Great White Sharks: the Biology of Carcharodon carcharias. Academic Press, San Diego.
Ayress, M. A. 1993. Ostracod biostratigraphy and paleoecology of the
Kokoamu Greensand and Otekaike Limestone (Late Oligocene to
Early Miocene), North Otago and South Canterbury, New Zealand.
Alcheringa 17:125–151.
Cappetta, H. 1987. Chondrichthyes II. Mesozoic and Cenozoic Elasmobranchii. Handbook of Paleoichthyology (H.-P. Schultze, ed.),
Vol. 3B. Gustav Fischer Verlag, Stuttgart, New York, 193 pp.
Casier, E. 1960. Note sur la collection des poissons pale´oce`nes et e´oce`nes de l’Enclave de Cabinda (Congo). Annales du Muse´e Royal du
Congo Belge, series A 3:1–48.
Chapman, F. 1918. Descriptions and revisions of the Cretaceous and